Origin of idea for the pilot episode
Most of the world's intelligence services publish information booklets detailing their basic functions.
If you look at a copy of the Background Series No. 8, "Political Violence and Terrorism", dated from before 9/11 and published by the Canadian Security Intelligence Service, you will find a brief listing of threats issued by major terrorist organizations. One such threat stated that the World Trade Centre would be attacked on September 11th, 2001.
This was a publically known threat. He said he was going to do it. Any writer for the series could have read this. There was probably a similar statement in whatever publications the CIA releases.
I gave my copy to a documentary filmmaker who lived with me, but you can probably dig up a copy if you really try. For that matter, did you know you can actually phone the CIA or CSIS? They have telephone numbers and public relations personnel. I recommend starting off by expressing an interest in becoming an intelligence officer. They will probably mail you an information package.
So, please. No more speculative arguments by those who have no desire to become informed.